I'm new to incubating eggs, raising new chicks... I have 9 hens (2 bsl's and 7 rir's). I have 7 chicks that were born on December 27. They were placed in the brooder (a 2'x6' box with a 2x2 box being used as a warmer). Temperature has been perfect using a 250w IR floodlight to keep warm. There is good ventilation, fresh water, and purina start and grow... All chicks have been healthy until I found one near death this am. It couldn't sit up, appeared to be gasping for air. It wouldn't take water... and acted like it kept going to sleep. I checked on it an hour later and it had died. I noticed what appeared to be what I call "pasty butt".. However its vent didn't appear blocked... Any advice? Do I need to worry about the other chickies?